1. Field of the Invention
The present invention relates generally to a method and apparatus for detecting engine knocking, and more particularly to a method and apparatus for detecting engine knocking which can accurately separate engine knocking vibration signals from background noise signals on the basis of waveforms of the detected engine vibration signals.
2. Description of the Prior Art
There are various well-known engine knocking detection methods and apparatus used to detect engine knocking in automotive vehicle engines. In these prior-art engine knocking detection methods and apparatus, conventionally, engine knocking vibration signals are detected by a vibration sensor and filtered through a band-pass filter. After that, the filtered signals are divided into two signals, namely an engine knocking vibration signal and a background noise signal, by rectifying and smoothing the detected vibration signals. These two signals are compared by a comparator in order to determine whether or not engine knocking has occurred.
In prior-art engine knocking detection methods and apparatus, however, since the vibration sensor tends to detect various mechanical vibrations other than engine knocking vibrations and additionally since the smoothing circuit cannot accurately distinguish small engine knocking vibration signals from comparable background noise signals or other mechanical vibration signals, prior-art engine knocking detection methods and apparatus are not sufficiently reliable.
The arrangement and the operation of a prior-art engine knocking detection apparatus will be described in more detail with reference to the attached drawings under DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS.